Blower and cleaner including the same

ABSTRACT

A blower designed to reduce noise generated between impeller blades and diffuser blades positioned around the impeller blades upon rotation of an impeller, and a cleaner including the same are disclosed. The diffuser blades are non-uniformly spaced from each other in a circumferential direction such that interaction between the plurality of impeller blades and the plurality of diffuser blades become irregular upon rotation of the impeller. Distances between the impeller blades and the diffuser blades are non-uniform. With this construction, the blower and the cleaner are reduced in BPF noise, thereby enhancing performance thereof.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. §119 of Korean Patent Application No. 2005-49762, filed on Jun. 10, 2005 and of Korean Patent Application No. 2005-62379, filed on Jul. 11, 2005 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a blower, and, more particularly, to a blower designed to reduce noise generated between impeller blades and diffuser blades positioned around the impeller blades upon rotation of an impeller, and a cleaner including the same.

2. Description of the Related Art

Generally, blowers are used for generating air flow or raising a pressure, and are classified into a centrifugal type, a mixed flow type, an axial flow type, and the like. The centrifugal blower refers to a blower in which an impeller including a plurality of circumferentially arranged blades sucks air from an outside into the blower, and discharges it radially from the blower while being rotated by a motor. At this time, a diffuser is located at an outlet of the impeller, and acts to convert dynamic pressure of fluid into static pressure thereof.

Such a centrifugal blower is used for a vacuum cleaner which cleans dust or foreign substances using a strong suction force. FIG. 1 is a plan view illustrating an impeller and a diffuser of a conventional centrifugal blower used for the vacuum cleaner. As shown in FIG. 1, a fan guide 3 is positioned around an outer periphery of an impeller 2 including a plurality of impeller blades 1, and is provided with a diffuser 5 including a plurality of diffuser blades 4.

Generally, the blower is designed to minimize a distance G between the impeller and the diffuser in consideration of efficiency and performance of the blower. As a result, when the impeller 2 rotates at a high speed to generate a high suction force, the impeller blades 1 periodically face diffuser blades 4, generating severe Blade Passage Frequency (BPF) noise.

Noise generated from the vacuum cleaner includes the BPF noise as mentioned above, noise caused by vibration of the motor, aeroacoustic noise from an air suction side, and the like. In particular, since severe BPF noise is generated at a specific frequency, it causes severe displeasure to a user or other persons surrounding the vacuum cleaner.

In order to solve the noise problem, a blower has been developed which includes a diffuser not having blades, and a three-dimensional impeller designed to compensate reduction in performance due to the diffuser not having the blades. One example of this blower is disclosed in Korean Patent Application Laid-open Publication No. 1998-59321. However, it is difficult to manufacture a small-sized three-dimensional impeller which can be applied to the vacuum cleaner, and when done, manufacturing costs of the small sized impeller are too high to apply the impeller to the vacuum cleaner.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide a blower, designed to reduce noise generated between an impeller rotating at a high speed and a diffuser positioned around the impeller without a significant increase in manufacturing costs, and a cleaner including the same.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

In accordance with the present invention, the above objects and aspects are achieved by providing a blower including an impeller including a plurality of impeller blades and being rotated by a motor, and a diffuser including a plurality of diffuser blades and being located around an outer periphery of the impeller, wherein the plurality of diffuser blades are non-uniformly spaced from each other in a circumferential direction so as to reduce noise caused by interaction between the plurality of impeller blades and the plurality of diffuser blades upon rotation of the impeller.

The plurality of diffuser blades may be arranged such that a central angle defined between a pair of adjacent diffuser blades is different from other central angles defined between other pairs of adjacent diffuser blades.

When one of the diffuser blades is defined as a reference blade, a central angle between a diffuser blade located at an xth position from the reference blade and a diffuser blade located at an x-1th position from the reference blade may be determined by the following Equation: $y = {y_{0} + {a\quad{\sin\left( {\frac{2\pi\quad x}{b} + c} \right)}}}$ or $y = {y_{0} + {a\quad{\mathbb{e}}^{- {({x/x_{0}})}}\quad{\sin\left( {\frac{2\pi\quad x}{b} + c} \right)}}}$

Here, x₀=n/2, y₀=360/n, n=the number of diffuser blades, and a, b, and c are constants.

The number of diffuser blades may be determined to have no common divisor except for 1 with respect to the number of the impeller blades.

The impeller and the diffuser may be arranged to have non-uniform distances between the impeller blades and the diffuser blades in order to strengthen noise reduction effect.

For this purpose, at least one of the impeller blades may be further spaced at a distal end thereof by a predetermined distance from an associated diffuser blade adjacent to the distal end of the impeller blade, in comparison to distances between other impeller blades and their associated diffuser blades.

Alternatively, at least one of the diffuser blades may be further spaced at a distal end thereof by a predetermined distance from an associated impeller blade adjacent to the distal end of the diffuser blade, in comparison to distances between other diffuser blades and their associated impeller blades.

In accordance with the present invention, the above objects and aspects are achieved by providing a cleaner including a blower including an impeller including a plurality of impeller blades and being rotated by a motor, and a diffuser including a plurality of diffuser blades and being located around an outer periphery of the impeller to generate suction force for intake of foreign substances, wherein first ends of the respective diffuser blades adjacent to the impeller are non-uniformly spaced from each other in a circumferential direction so as to allow variation in period of the impeller blades passing the diffuser blades upon rotation of the impeller.

The plurality of diffuser blades are arranged such that a central angle defined between a pair of adjacent diffuser blades is different from a central angle defined between another pair of adjacent diffuser blades, and as for a specific reference for the arrangement of the diffuser blades, the above equation may be applied.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, of which:

FIG. 1 is a plan view illustrating an impeller and a diffuser of a conventional centrifugal blower used for a vacuum cleaner;

FIG. 2 is a view illustrating a cleaner in accordance with the present invention;

FIG. 3 is a cross-sectional view illustrating the construction of a body of the cleaner;

FIG. 4 is a cross-sectional view illustrating the construction of a blower in accordance with a first embodiment of the present invention;

FIG. 5 is a perspective view illustrating an impeller and a fan guide of the blower;

FIG. 6 is a view illustrating an example of irregular disposition of diffuser blades in the blower in a circumferential direction;

FIG. 7 is a plan view illustrating an impeller and a diffuser in a blower in accordance with a second embodiment of the present invention; and

FIG. 8 is a plan view illustrating an impeller and a diffuser in a blower in accordance with a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout the drawings. The embodiments are described below to explain the present invention by referring to the figures.

FIG. 2 is a view illustrating an appearance of a cleaner in accordance with the present invention, and FIG. 3 is a cross-sectional view illustrating the construction of a body of the cleaner.

As shown in FIGS. 2 and 3, the cleaner of the present invention includes a suction unit 10 to suck dust or foreign substances via suction force, and a body 20 which includes a filter to collect the dust sucked through the suction unit, and a blower 30 to generate the suction force.

The cleaner further includes a connection hose 11 and a connection pipe 12 arranged to transfer the suction force generated by the blower 30 to the suction unit 10 between the body 20 and the suction unit 10, and a handle 13 between the connection hose 11 and the connection pipe 12. The handle 12 has a controller (not shown) integrally provided therein so as to allow easy operation by a user. The connection hose 11 is made from a stretchable ribbed pipe. The connection hose 11 is connected at one end to the body 20, and at the other end to the handle 13. The connection pipe 12 is connected at one end to the suction unit 10, and at the other end to the handle 13 so that an operator can freely move the cleaner to clean floor.

The body 20 is partitioned into a dust collecting compartment 20 a in which the filtering unit is positioned, and a suction compartment 20 b in which the blower 30 is positioned. Specifically, the dust collecting compartment 20 a is provided with a dust bag 22 to collect the dust, and a filter 23 to filter fine dust which is not filtered by the dust bag 22. The suction compartment 20 b is provided with the blower 30 to generate the suction force for intake of the foreign substances.

FIG. 4 is a cross-sectional view illustrating the construction of a blower in accordance with a first embodiment of the invention, and FIG. 5 is a perspective view illustrating an impeller and a fan guide of the blower. As shown in FIGS. 4 and 5, the blower 30 includes an impeller cover 31 which has a suction port 31 a formed on an upper surface, and a motor case 32 coupled to a lower side of the impeller cover 31, which defines an outer appearance of the blower 30.

An impeller 40, and a fan guide 50 are positioned inside the impeller cover 31. The impeller 40 includes a plurality of impeller blades 41 to suck air through the suction port 31 a. Each of the impeller blades 41 is curved circumferentially between an upper plate 42 and a lower plate 43 of the impeller 40 such that air sucked through the suction port 31 a is discharged via the blower 30 in a radial direction. The blower 30 includes a plurality of diffuser blades 61 around an upper periphery of the fan guide 50, and acts to raise a pressure of the air passing through the impeller 40. Thus, when the impeller 40 is mounted above the fan guide 50, the diffuser 60 is positioned around the impeller 40 while being separated a predetermined distance from the impeller 40. The fan guide 50 is formed at a lower surface with a return channel 51 which guides air passing through the diffuser 60 towards a motor 33.

The motor 33 is positioned within the motor case 32, and connected to the impeller 40 via a rotational shaft 34 to rotate the impeller 40. The motor case 32 has an air vent 35 formed at one side, through which air passing through the motor 33 is discharged to an outside of the motor case 32.

Thus, as the cleaner is operated by the controller (not shown), the impeller 40 is rotated by the motor 33 to suck air through the suction port 31 a and to discharge the air in the radial direction. The discharged air is raised in pressure while passing through the diffuser 60. After passing through the diffuser 60, the air is guided towards a lower side of the fan guide 50, and is induced towards the motor 33 through the return channel 51. The induced air cools the motor 33 while passing through the motor 33, and is finally discharged through the discharge port 35 of the motor case 32.

When the impeller 40 rotates at a high speed in order to generate a high suction force, the plurality of impeller blades 41 periodically faces the diffuser blades 61 with a narrow distance therebetween, and generates strong BPF noise. This noise is harsh to the ear. According to the present invention, noise generated between the impeller blades 41 and the diffuser blades 61 is modulated by constituting the impeller 40 and the diffuser 60 such that the plurality of diffuser blades are non-uniformly arranged in the circumferential direction so as to provide non-uniform interaction between the impeller blades 41 and the diffuser blades 61, thereby reducing the noise.

FIG. 6 is a view illustrating an example of the arrangement of the diffuser blades in the blower in which the diffuser blades are non-uniformly arranged in the circumferential direction. In a circle, a circumferential distance between two points significantly changes according to a central angle defined between the points. Thus, as shown in FIG. 6, the plurality of diffuser blades 61 can be non-uniformly arranged by defining a central angle θ₁ between a pair of adjacent diffuser blades (for example, 61 a and 61 b) to be different from a central angle θ₂ defined between another pair of adjacent diffuser blades (for example, 61 f and 61 g). Here, the term “central angle between the pair of adjacent diffuser blades” means the central angle formed by a pair of first end (A and B or F and C) of the diffuser blades adjacent to the impeller 40.

If the number of diffuser blades and the number of impeller blades are determined, a reference for determining the central angle between each pair of adjacent diffuser blades can be obtained through experiment. However, in this case, there is inconvenience in that when changing the numbers of impeller blades and of diffuser blades due to a design of the blower, it is necessary to perform new experiments to define a new reference.

Thus, as a reference for defining the central angle between the pair of adjacent diffuser blades, one of the following equations can be applied. Although the following equations are not obtained according to a particular physical theory, they are adopted to allow the plurality of diffuser, blades 61 to be suitably arranged while being non-uniformly separated from each other in the circumferential direction. $\begin{matrix} {y = {y_{0} + {a\quad{\sin\left( {\frac{2\pi\quad x}{b} + c} \right)}}}} & \left\lbrack {{Equation}\quad 1} \right\rbrack \end{matrix}$

Here, when one of the diffuser blades is defined as a reference blade 61 a, y is a central angle defined between a diffuser blade located at an xth position from the reference blade 61 a and a diffuser blade located at an x-1th position from the reference blade 61 a. In addition, x₀=n/2, y₀=360/n, n=the number of diffuser blades, and a, b, and c are constants.

For example, as shown in FIG. 6, if the number of diffuser blades is eleven (n=11), central angles between each pair of adjacent diffuser blades can be defined by the Equation 1, and are shown in Table 1. At this time, Constants a, b, and c are 1.4831, 2.8581, and 4.8540, respectively, and are determined by trial and error. TABLE 1 x y (degree) 1 33.7589 (θ ₁) 2 32.9841 (θ ₂) 3 31.3942 (θ ₃) 4 34.0361 (θ ₄) 5 32.5234 (θ ₅) 6 31.6579 (θ ₆) 7 34.1870 (θ ₇) 8 32.0824 (θ ₈) 9 32.0250 (θ ₉) 10  33.1971 (θ ₁₀) 11  31.7036 (θ ₁₁) — —

In table 1, y=33.7589 at x=1 means that a central angle θ₁ defined between a reference blade 61 a and a first diffuser blade 61 b from the reference blade 61 a is 33.7589 degrees. In addition, y=31.6579 at x=6 means that a central angle θ₆ defined between a sixth reference blade 61 g and a fifth diffuser blade 61 f from the reference blade 61 a is 31.6579 degrees.

As such, the central angle between the pair of adjacent diffuser blades can be determined by Equation 1, and even if the number of the diffuser blades is changed due to the design, appropriate central angles corresponding to the changed number of diffuser blades can be easily obtained by Equation 1.

Similarly, the central angle between the pair of adjacent diffuser blades can be obtained using the following Equation 2. Here, as in Equation 1, x₀=n/2, n=the number of diffuser blades, and a, b, and c are constants. $\begin{matrix} {y = {y_{0} + {a\quad{\mathbb{e}}^{- {({x/x_{0}})}}\quad{\sin\left( {\frac{2\pi\quad x}{b} + c} \right)}}}} & \left\lbrack {{Equation}\quad 2} \right\rbrack \end{matrix}$

For example, if the number of diffuser blades is eleven (n=11), central angles between each pair of adjacent diffuser blades can be defined by Equation 2, and are shown in Table 2. TABLE 2 X y (degree) 1 33.5875 2 32.9057 3 31.9546 4 33.3597 5 32.6451 6 32.3681 7 33.1459 8 32.5866 9 32.6004 10 33.9757 11 31.5888 — —

As can be appreciated from Table 2, the central angle between the pair of adjacent diffuser blades can be suitably determined by Equation 2.

Meanwhile, the number of diffuser blades 61 is determined to have no common divisor except for 1 with respect to the number of the impeller blades 41. With this construction, interaction between the diffuser blades 61 and the impeller blades 41 is minimized upon rotation of the impeller 40, reducing the BPF noise. For example, FIG. 6 shows the case where the number of diffuser blades 61 is 11, and the number of impeller blades 41 is 9.

In addition, the blower and the vacuum cleaner of the invention are designed to reduce noise by arranging the impeller and the diffuser to have non-uniform distances between the impeller blades and the diffuser blades as well as by arranging the diffuser blades to be non-uniformly spaced from each other in the circumferential direction as described above.

FIG. 7 is a plan view illustrating an impeller and a diffuser in a blower in accordance with a second embodiment of the present invention, and FIG. 8 is a plan view illustrating an impeller and a diffuser in a blower in accordance with a third embodiment of the present invention. The embodiments shown in FIGS. 7 and 8 are modifications of the embodiment shown in FIG. 6.

As shown in FIG. 7, at least one impeller blade 41 a of the impeller blades may be further spaced at a distal end thereof by a predetermined distance d1 from an associated diffuser blade adjacent to the distal end of the impeller blade 41 a, in comparison to distances between other impeller blades 41 and their associated diffuser blades 61. Alternatively, as shown in FIG. 8, at least one diffuser blade 61 c, 61 f or 61 j of the diffuser blades may be further spaced at a distal end thereof by a predetermined distance d2 from an associated impeller blade adjacent to the distal end of the diffuser blade 61 c, 61 f or 61 j, in comparison to distances between other diffuser blades 61 and their associated impeller blades 41. With this construction, such a distance d1 or d2 acts to change a passage period of the impeller blades 41 with respect to the diffuser blades 61, and thus reduces noise caused by the interaction between the impeller blades 41 and the diffuser blades 61. In the meantime, if the distance between the impeller 40 and the diffuser 60 is significantly increased, the performance of the blower can be deteriorated. Thus, it is desirable to adjust the distance d1 or d2 such that a distance between the impeller 40 and the diffuser 60 is within 2% of an outer diameter of the impeller 40.

As apparent from the above description, one of the advantageous effects of the invention is that the impeller blades and the diffuser blades are arranged to have irregular interaction therebetween in the blower, thereby reducing BPF noise from the blower.

In addition, it is another advantageous effect of the invention that, since there is substantially no additional costs for achieving the above advantageous effects due to the structure of the invention, the diffuser can be easily applied to products such as a vacuum cleaner, thereby enhancing quality of the products.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that various modifications, additions and substitutions may be made in these embodiments without departing from the principle and spirit of the invention, the scope of which defined in the claims and their equivalents. 

1. A blower, comprising: an impeller including a plurality of impeller blades and being rotated by a motor; and a diffuser including a plurality of diffuser blades and being located around an outer periphery of the impeller, wherein the plurality of diffuser blades are non-uniformly spaced from each other in a circumferential direction so as to reduce noise caused by interaction between the plurality of impeller blades and the plurality of diffuser blades upon rotation of the impeller.
 2. The blower according to claim 1, wherein the plurality of diffuser blades are arranged such that a central angle defined between a pair of adjacent diffuser blades is different from other central angles defined between other pairs of adjacent diffuser blades.
 3. The blower according to claim 2, wherein, when one of the diffuser blades is defined as a reference blade, a central angle between a diffuser blade located at an xth position from the reference blade and a diffuser blade located at an x-1th position from the reference blade is determined by the following Equation: $y = {y_{0} + {a\quad{\sin\left( {\frac{2\pi\quad x}{b} + c} \right)}}}$ in which y₀=360/n, n=the number of diffuser blades, and a, b, and c are constants.
 4. The blower according to claim 2, wherein, when one of the diffuser blades is defined as a reference blade, a central angle between a diffuser blade located at an xth position from the reference blade and a diffuser blade located at an x-1th position from the reference blade is determined by the following Equation: $y = {y_{0} + {a\quad{\mathbb{e}}^{- {({x/x_{0}})}}\quad{\sin\left( {\frac{2\pi\quad x}{b} + c} \right)}}}$ in which x₀=n/2, y₀=360/n, n=the number of diffuser blades, and a, b, and c are constants.
 5. The blower according to claim 1, wherein the number of diffuser blades is determined to have no common divisor except for 1 with respect to the number of the impeller blades.
 6. The blower according to claim 1, wherein distances between the impeller blades and the diffuser blades are non-uniform.
 7. The blower according to claim 6, wherein at least one of the impeller blades is further spaced at a distal end thereof by a predetermined distance from an associated diffuser blade adjacent to the distal end of the impeller blade, in comparison to distances between other impeller blades and their associated diffuser blades.
 8. The blower according to claim 6, wherein at least one of the diffuser blades is further spaced at a distal end thereof by a predetermined distance from an associated impeller blade adjacent to the distal end of the diffuser blade, in comparison to distances between other diffuser blades and their associated impeller blades.
 9. A cleaner including a blower, comprising: an impeller including a plurality of impeller blades and being rotated by a motor; and a diffuser including a plurality of diffuser blades and being located around an outer periphery of the impeller to generate suction force for intake of foreign substances, wherein first ends of the respective diffuser blades adjacent to the impeller are non-uniformly spaced from each other in a circumferential direction so as to allow variation in period of the impeller blades passing the diffuser blades upon rotation of the impeller.
 10. The cleaner according to claim 9, wherein the plurality of diffuser blades are arranged such that a central angle defined between a pair of adjacent diffuser blades is different from other central angles defined between other pairs of adjacent diffuser blades.
 11. The cleaner according to claim 10, wherein, when one of the diffuser blades is defined as a reference blade, a central angle between a diffuser blade located at an xth position from the reference blade and a diffuser blade located at an x-1th position from the reference blade is determined by the following Equation: $y = {y_{0} + {a\quad{\sin\left( {\frac{2\pi\quad x}{b} + c} \right)}}}$ in which y₀=360/n, n=the number of diffuser blades, and a, b, and c are constants.
 12. The cleaner according to claim 10, wherein, when one of the diffuser blades is defined as a reference blade, a central angle between a diffuser blade located at an xth position from the reference blade and a diffuser blade located at an x-1th position from the reference blade is determined by the following Equation: $y = {y_{0} + {a\quad{\mathbb{e}}^{- {({x/x_{0}})}}\quad{\sin\left( {\frac{2\pi\quad x}{b} + c} \right)}}}$ in which x₀=n/2, y₀=360/n, n=the number of diffuser blades, and a, b, and c are constants.
 13. The cleaner according to claim 9, wherein the number of diffuser blades is determined to have no common divisor except for 1 with respect to the number of the impeller blades.
 14. The cleaner according to claim 9, wherein distances between the impeller blades and the diffuser blades are non-uniform.
 15. The cleaner according to claim 14, wherein at least one of the impeller blades is further spaced at a distal end thereof by a predetermined distance from an associated diffuser blade adjacent to the distal end of the impeller blade, in comparison to distances between other impeller blades and their associated diffuser blades.
 16. The cleaner according to claim 14, wherein at least one of the diffuser blades is further spaced at a distal end thereof by a predetermined distance from an associated impeller blade adjacent to the distal end of the diffuser blade, in comparison to distances between other diffuser blades and their associated impeller blades. 